21 research outputs found

    Debat: Historien kan sælges

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    One of the permanent concerns in the international scenario is the study of the consequences of nuclear and radiological accidents and other events that lead to the contamination of the environment and the exposure of members of the public as a consequence of this contamination. Decision-making in such situations need to be based in solid technical criteria but must also take into account the actual prevailing circumstance in order to reach optimized measures to protect people and the environment. The Multi-criteria Analysis Method is already being used for similar applications in some European countries but it is necessary that the criteria are established taking in account economic, social and climatic aspects that can affect the selection of protective measures applicable to specific regions, and the selection of the different weights to be associated to the different criteria that are to be applied to different social-politic environments. The present work describes the developments to support the decision making process for the implementation of protective measures to protect the public in situations of radiological accidents in Brazil, the steps already developed and the current status of the system under development, discusses the difficulties found and stresses the needs for future developments

    Anti-trypanosomal activity of pentacyclic triterpenes isolated from Austroplenckia populnea (Celastraceae) Atividade anti-tripanosomicida de triterpenes pentacíclicos isolados de Austroplenckia populnea (Celastraceae)

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    Four pentacyclic triterpenes isolated from Austroplenckia populnea and four compounds of known anti T. cruzi or anti-malarial activity were tested. Of those triterpenes tested 20alpha-hydroxy-tingenone showed high activity, epikatonic acid was less active, while populnilic and populninic acids were inactive against the trypanosome of the subgenus Schizotrypanum tested. Benzonidazole, nifurtimox, ketoconazole and primaquine presented a remarkable dose-dependent inhibitory effect reaching practically to a total growth inhibition of the parasite at the end of incubation time. The trypanosome tested appear to be a suitable model for preliminary screen for anti T. (S.) cruzi compounds.<br>Foram testados quatro triterpenos pentacíclicos isolados de Austroplenckia populnea e quatro compostos de conhecida atividade anti-T. cruzi ou anti-malárica. Dos triterpenos testados 20alfa-hidroxi-tingenona mostrou atividade elevada, ácido epicatônico foi menos ativo, enquanto ácido populnílico e populnínico foram inativos contra o tripanossoma do subgênero Schizotrypanum testado. Benzonidazole, nifurtimox, cetoconazole e primaquina apresentaram efeito inibitório dose-dependente atingindo praticamente a inibição total do crescimento do parasita no final do tempo de incubação. O tripanossoma testado mostrou ser um modelo adequado para uma seleção preliminar de compostos anti. T. (S.) cruzi

    First measurement of the Zμ+μZ\rightarrow \mu^+ \mu^- angular coefficients in the forward region of pppp collisions at s=13\sqrt{s}=13 TeV

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    International audienceThe first study of the angular distribution of μ+μ\mu^+ \mu^- pairs produced in the forward rapidity region via the Drell-Yan reaction ppγ/Z+Xl+l+Xpp \rightarrow \gamma^{*}/Z +X \rightarrow l^+ l^- + X is presented, using data collected with the LHCb detector at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 5.1 fb1\rm{fb}^{-1}. The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the ZZ-boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton

    Measurement of the charm mixing parameter yCPyCPKπy_{CP} - y_{CP}^{K\pi} using two-body D0D^0 meson decays

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    International audienceA measurement of the ratios of the effective decay widths of D0→π-π+ and D0→K-K+ decays over that of D0→K-π+ decays is performed with the LHCb experiment using proton–proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6  fb-1. These observables give access to the charm mixing parameters yCPππ-yCPKπ and yCPKK-yCPKπ, and are measured as yCPππ-yCPKπ=(6.57±0.53±0.16)×10-3, yCPKK-yCPKπ=(7.08±0.30±0.14)×10-3, where the first uncertainties are statistical and the second systematic. The combination of the two measurements is yCP-yCPKπ=(6.96±0.26±0.13)×10-3, which is four times more precise than the previous world average

    Measurement of the Nuclear Modification Factor and Prompt Charged Particle Production in pPbp-Pb and pppp Collisions at sNN\sqrt {s_{NN}}=5  TeV

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    International audienceThe production of prompt charged particles in proton-lead collisions and in proton-proton collisions at the nucleon-nucleon center-of-mass energy sNN=5  TeV is studied at LHCb as a function of pseudorapidity (η) and transverse momentum (pT) with respect to the proton beam direction. The nuclear modification factor for charged particles is determined as a function of η between -4.8&lt;η&lt;-2.5 (backward region) and 2.0&lt;η&lt;4.8 (forward region), and pT between 0.2&lt;pT&lt;8.0  GeV/c. The results show a suppression of charged particle production in proton-lead collisions relative to proton-proton collisions in the forward region and an enhancement in the backward region for pT larger than 1.5  GeV/c. This measurement constrains nuclear PDFs and saturation models at previously unexplored values of the parton momentum fraction down to 10-6
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